We Now Know Why Naval Sonar Leads To Mass Whale Strandings

But how can an animal perfectly adapted to life underwater, with the ability to dive 2,000 meters (6,500 feet), end up with the same problem as a panicky scuba diver?

"In the presence of sonar they are stressed and swim vigorously away from the sound source, changing their diving pattern," lead author Yara Bernaldo de Quiros told AFP.

"The stress response, in other words, overrides the diving response, which makes the animals accumulate nitrogen. It's like an adrenalin shot."

The team points out that the response can vary from whale to whale, but it explains why atypical strandings often occur where naval sonar has been deployed. The conclusions are drawn from autopsies of dead whales, although a handful of animals were killed by other threats inflicted by humans, such as collisions with ships or entanglement in fishing nets, as well as disease.

The authors note that to mitigate the impacts of sonar on beaked whales, we must ban its use in areas where they're found. A moratorium on the use of MFAS around the Canary Islands in 2004 shows just how well this works – no atypical strandings have been seen since. The researchers urge other countries where sonar is deployed, such as the US, Greece, Italy, and Japan, to follow suit.